powerpc: Access local paca after hard irq disabled

In hard_irq_disable(), we accessed the PACA before we hard disabled
the interrupts, potentially causing a warning as get_paca() will
us debug_smp_processor_id().

Move that to after the disabling, and also use local_paca directly
rather than get_paca() to avoid several redundant and useless checks.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/hw_irq.h

@@ -96,10 +96,11 @@ static inline bool arch_irqs_disabled(void)
 #endif
 
 #define hard_irq_disable()	do {			\
-	u8 _was_enabled = get_paca()->soft_enabled;	\
+	u8 _was_enabled;				\
 	__hard_irq_disable();				\
-	get_paca()->soft_enabled = 0;			\
-	get_paca()->irq_happened |= PACA_IRQ_HARD_DIS;	\
+	_was_enabled = local_paca->soft_enabled;	\
+	local_paca->soft_enabled = 0;			\
+	local_paca->irq_happened |= PACA_IRQ_HARD_DIS;	\
 	if (_was_enabled)				\
 		trace_hardirqs_off();			\
 } while(0)